The invention relates to a hybrid gas generator which contains an ignitable, gas-generating solid charge and a storage chamber containing a gas.
A hybrid gas generator for air bags is known from EP 0 616 578 B1, which contains an ignitable solid charge in a combustion chamber and a pressurized gas in a storage chamber. Upon the initiation of the gas generator, an ignition element ignites the solid charge. A hollow piston is driven by the combustion gases which are generated, with the hollow piston pushing through a closure element which closes the storage chamber, and with the pressurized gas contained in the storage chamber being able to flow out to the outlet. Moreover, the combustion gases generated by the solid charge flow into the storage chamber, where they mix with the compressed gas. When the closure element is destroyed, first of all cold compressed gas flows to the outlet. This prevents the hot combustion gases from arriving in the air bag first. Subsequently, a mixture of cold gas and combustion gas flows into the air bag.
Moreover, a hybrid gas generator is known from EP 0 669 231 A2, where a mixing chamber is arranged between a combustion chamber containing the solid charge and a storage chamber containing a compressed gas. The combustion chamber and the storage chamber are sealed by sealing discs which are destroyed by the combustion gases of the solid charge. In this respect, the combustion gas and the cold gas penetrate from opposite directions into the mixing chamber, with the flowing-out being impeded as a result. Moreover, the hot combustion gas loaded with harmful substances flows out initially because the sealing disc of the combustion chamber is the first one to be destroyed.
The known hybrid gas generators have a pressure buildup behaviour determined by their construction, with the maximum pressure and the pressure increase gradient being specified. In the process, the air bag connected to the gas generator is inflated very quickly and in one go. In the process, the passengers can be injured by the air bag if they are "out of position".